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Biomedical subjects

H C Thompson

Publications and source records attributed to H C Thompson.

18 recordsLinked to original sources
PubMed1992

Determination of aflatoxins in food products by chromatography.

Several chromatographic methods for the determination of aflatoxins in agricultural and food products are reviewed. During the past two decades, identification and determination of aflatoxins were done by thin-layer chromatography (TLC) because it was easy, fast and inexpensive. However, high-performance liquid chromatography (HPLC) using fluorescence detection is now the method of choice for determining aflatoxins and is also growing in popularity for their identification. The reasons for selecting HPLC over TLC can be summarized as the ability to analyze for a wide variety of compounds, including compounds that are easily degraded by heat, light or air, the ease of adaptation to confirmatory procedures, the potential for automation and the dramatic improvement in instrumentation, including the development of increasingly sensitive fluorescence and electrochemical detectors and short, high-resolution, reversed-phase columns.

Aflatoxins↗
PubMed1992

Pharmacokinetics of high dose thiotepa in children undergoing autologous bone marrow transplantation.

Pharmacokinetics of high dose thiotepa was studied in 10 children who received this drug as a 2 h infusion at a dose of 300 mg/m2 daily for 3 days. The thiotepa was quantitated using a modification of a previously published gas chromatographic method. Samples were obtained at predetermined times post infusion. The peak plasma concentrations immediately following the infusion ranged from 5.5 to 25.2 (2.0 +/- 6.6) mg/l and the 8 h post infusion ranged from 0.06 to 0.7 (0.32 +/- 0.21) mg/l. The disposition of thiotepa was best described as a simple one compartment open model. The mean (+/- SEM) values for apparent elimination half-life (t1/2 beta), total plasma clearance (CL) and steady volume of distribution (VDss) were 1.3 x h, 11.25 (1.73) l/h/m2 and 19.38 (2.58) l/m2 respectively. In conclusion the pharmacokinetics of high dose thiotepa in children between 2 and 12 years of age do not appear to vary from those reported in children receiving 75 mg/m2 or adults receiving similar doses.

Bone Marrow Transplantation↗
PubMed1978

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Child↗
PubMed1977

Management criteria, recording of performance, and peer review of tonsillopharyngitis.

As part of a national study to formulate criteria for chart audit of quality assurance of child health care, criteria were developed for diagnosis and management of tonsillopharyngitis. These criteria were validated by pediatricians and family physicians in academic medicine and in practice. They were judged relevant to the medical care process and patient outcome by both. The selected criteria were also recommended by the majority of two large physician groups for use in peer review. In the first three phases of the study most of these criteria were said to be performed and recorded by a majority of physicians. However, in the fourth (community) phase, when charts of 166 primary-care physicians were actually audited, documentation was so poor that peer review by chart audit would be impractical at present.

Child↗
PubMed1977

Harvester ant sensitivity: in vitro and in vivo studies using whole body extracts and venom.

Harvester ant stings by Pogonomyrmex maricopa (Pm) or Pogonomyrmex rugosus (Pr) resulted in serious reactions in 8 patients, 4 with generalized reactions and 1 with large local reactions. Exposure to one species in the genus Pogonomyrmex (P) appeared to cross-sensitize ant-sensitive patients to other species in the same genus as evidenced by skin testing and leukocyte histamine release, but these patients were less sensitive to extracts from other stinging Hymenoptera, including bee, wasp, yellow jacket, hornet, and Formica ant. Pr ant venom was obtained by electrical stimulation of live ants for leukocyte histamine release studies. The venom preparation was considerably more effective in inducing histamine release than a body extract derived from gasters, the posterior abdominal segments. Rabbits immunized with an extract from one species produced precipitating antibodies against the injected extract withich cross-reacted with extracts from other species of harvester ant, but not with other stinging Hymenoptera. Humans and rabbits appear to react to certain genus-specific antigens present in Pogonomyrmex whole body extracts. Proper identification of the offending ant is crucial for proper testing and treatment of ant-sensitive patients.

Animals↗
PubMed1976

Quality assurance of ambulatory child health care opinions of practicing physicians about proposed criteria.

This paper reports the opinions of a representative sample of 1,329 physicians providing primary care regarding criteria developed by the Joint Committee on Quality Assurance for evaluation of ambulatory child health care. Areas of care were health supervision (in four age ranges), tonsillopharyngitis, bronchial asthma, and urinary infection. The criteria had been previously appraised by 452 "experts"--academicians and practitioners. Physicians rated criteria for relevance to health outcome, and desirability for use in peer review. They also stated whether they usually performed and recorded each item and gave reasons for not recording. Agreement between the pediatricians and other physicians of the sample and the "experts" was close regarding relevance to health outcome, but many fewer criteria were recommended for peer review by the sample. A significant number of respondents said they performed but did not record many of the criteria. Documentation of only abnormal findings was the main reason given for not recording. Criteria dealing with developmental or behavioral assessment or with counseling were rated lower in all categories than more easily measured items.

Adolescent↗
PubMed1976

Office records in the evaluation of quality of care.

Trained reviewers audited 10,500 charts in the offices of 166 pediatricians and family physicians. Criteria for child health supervision and three diseases had been previously validated for relevance to health outcome and suitability for peer review. Overall documentation of criteria was approximately 50 per cent. Measurements and laboratory data were recorded frequently; counseling items infrequently. Pediatricians documented health supervision items more often than family physicians. Members of large groups recorded more than those in solo practice or small groups. The presence of equipment considered important for health care did not correlate with percentage of recording. The method of review was judged accurate and acceptable by physicians, but only 50 per cent said the results accurately portrayed their performance. Lack of accurate recording may make it impossible to achieve valid peer review of ambulatory child care.

Adolescent↗
PubMed1976

Biological properties of an immunogenic pneumococcal subcellular preparation.

A subcellular fraction, designated PSP-3R, prepared from rough, type 3R Streptococcus pneumoniae is described, which affords excellent protection to mice against challenge with smooth organisms of the homologous serotype 3S and significant protection against heterologous challenge with serotypes 1S and 2S. Adjuvant enhances the protective capacity of the vaccine but is not necessary for immunogenicity. Protection induced by PSP-3R can be passively transferred tp normal mice with serum from actively immunized animals. The protective capacity can be completely absorbed out with rough or smooth type 3 organisms but not with rough type 1R or 2R cells. PSP-3R immune serum was tested in a passive hemagglutination assay against type 3 capsular polysaccharide-coated erythrocytes and found to have no detectable anticapsular antibody. The possible identity of the immunogen (s) in the vaccine is discussed.

Animals↗
PubMed1976

Immediate skin-test reactivity in a general population sample.

To assess the prevalence and distribution of allergic skin-test reactions in a general population sample, allergy prick tests were applied to 3101 subjects older than 2 years of age. Test materials included allergens common to the Tucson environment, and subjects were randomly stratified by age, sex, and socioeconomic status. No difference in the prevalence of measurable reactions was found among male subjects versus female subjects. A definite age relation was apparent, however, with the peak prevalence of reactivity (more than 40%) occurring during the third decade, and falling rapidly past age 50. When present, reactions tended to be multiple, highly reproducible, and more frequent among those in the higher socioeconomic strata. The prick test was judged to be a useful tool for the assessment of atopy.

Age Factors↗
PubMed1976

Management criteria, documentation, and peer review of initial urinary tract infection.

During part of a national study to formulate criteria for chart audit of quality assurance of child health care, criteria were developed for diagnosis and management of urinary tract infections. These criteria were validated by pediatricians and family physicians in academic medicine and in practice. They were judged relevant to the medical care process and patient outcome by both. The selected criteria were also recommended by the majority of two large physician groups for use in peer review. An important aspect of the study assessed the frequency of performing and recording indicated procedures or tests. In the first three phases of the study these criteria were said to be performed and recorded by a large majority of physicians. However, in the fourth (community) phase, when charts of 166 primary care physicians were actually audited, documentation was so poor that peer review by chart audit would be impractical at present. Assuming proper documentation of the medical care process, similar criteria could be used for chart audit, clinical research, and educational purposes. Since the diagnostic and management process of initial urinary tract infection is established, development of structured health care forms and education in proper record-keeping are two important challenges for those interested in the evaluation of ambulatory care.

Adolescent↗
PubMed1975

Cromolyn sodium in the treatment of children with severe, perennial asthma.

Cromolyn sodium is a recently introduced drug used in the prophylactic treatment of severe, perennial, bronchial asthma, particularly in the pediatric age group. In a multicenter trial, 276 chronic asthmatic patients of eight pediatric allergists entered a randomized, double-blind, placebo-controlled, crossover study lasting 12 weeks. Test compounds of cromolyn sodium or placebo were inhaled four times a day, and daily scores were kept of symptom severity as well as frequency of use of other medications. Patients had statistically significant lower average daily symptom scores when treated with cromolyn sodium as compared to treatment with placebo. A strong subjective preference for cromolyn sodium was expressed by 60% of those completing the trial, versus 9% for placebo. The patients' need for other symptomatic medications also dropped significantly during the cromolyn treatment period.

Adolescent↗
PubMedDate not supplied

Characterization of iodine derivatives of aflatoxin B1 and G1 by thermospray mass spectrometry.

Thermospray mass spectrometry (TSMS) was used to identify the derivatives formed when iodine is reacted with aflatoxins B1 and G1 at approximately 70 degrees C to enhance fluorescence. It was found that stable derivatives were formed by addition of an iodine atom and a methoxy group across the double bond located on the furan ring of the aflatoxin B1 and G1 molecules. TSMS and TSMS/MS daughter spectra of the reaction products of aflatoxin B1 and G1 with iodine provide evidence of the addition of each moiety to produce the iodo-methoxy derivative. The addition of an iodine atom to one carbon and a methoxy group to the other carbon of the furan ring provided molecular weights of 470 and 486 for the products of aflatoxin B1 and G1, respectively.

Aflatoxin B1↗